Technical Field
The present invention relates to a vehicle braking technology, and more particularly, to a device and method for braking.
Background Art
A brake device is a mechanical device that uses a force generated by an operating force of a driver or an auxiliary power, e.g. a friction force, to convert kinetic energy of vehicles including a car, heavy equipment, etc. to thermal energy in order to perform braking. Brake devices used in the vehicles, etc. include a service brake that operates by a driver's operation during driving and a parking brake that operates by a driver's operation for stopping or parking a vehicle.
The brake devices are classified as friction type and non-friction type depending on whether a friction force is used or not. The friction type includes a vacuum brakes air hydraulic brake, etc. and the non-friction type includes an electronic brake, a fluid type brake, etc. The hydraulic type among the friction type brakes is used in most cars, and a driver's force of stepping on a pedal is transferred via hydraulic pressure to be converted to a braking force on wheels. Also, the air brake is used much in large vehicles including a bus, a truck, etc.
Meanwhile, the brake devices may be classified as a positive brake system and a negative brake system. The positive brake system refers to a brake system that is operated so that a pressure is supplied to brake disks that are basically not in contact so that the brake disks comes in contact for stopping a vehicle or lowering a speed of the vehicle. Conversely, the negative brake system refers to a brake system that is operated so that a pressure is supplied to brake disks that are basically in contact so that the brake disks are detached for moving a vehicle.
Here, in the negative brake system, although a brake in a normal state operates by a release of a pressure under a driver's control, in a situation where a vehicle stalls while driving, a situation where an engine has stopped abnormally, a situation where an abnormality has occurred in an electric system, and a situation where an abnormality has occurred in a hydraulic or pneumatic system, a pressure supplied to a parking brake is automatically released to be in a state where a braking force of the parking brake is applied.
In such an emergency situation, in order to repair the vehicle, the braking force caused by the parking brake has to be released or the vehicle itself has to be lifted and carried.
Here, the braking force caused by the parking brake must be released when moving the vehicle itself is impossible or difficult, and for this, a method of releasing the braking force has been used conventionally where a brake system itself is disassembled or hole is made that communicates with a brake chamber to supply a pressure to a brake by a separate pressure supplying means.
However, since the work required for disassembling the brake system itself in the vehicle or artificially making a hole at the brake system to supply the pressure, the work has to be done by an expert using specific equipment for a long time.
Meanwhile, when a pressure supplied to a parking brake is automatically released due to an abnormality such as a failure of a service brake that occurs during driving a vehicle, the vehicle suddenly stops due to a braking force being applied to the parking brake. In this manner, when the vehicle suddenly stops by the parking brake, a dangerous situation may occur in which a driver or an occupant collides with an inner structure of the vehicle by severely leaning to one side, the vehicle spins out of control due to losing balance, etc.